ASK (apoptosis signal-regulating kinase) has been described as a mitogen-activated protein kinase. ASK-1 and ASK-2 have been described as members of the ASK family. ASK-1 is a MAPKKK (mitogen-activated protein kinase kinase kinase). Human and mouse ASK-1 consist of 1374 and 1380 amino acids, respectively, and possess a serine/threonine kinase domain. ASK-1 is activated by environmental stress. The stimuli include inter alia H2O2, LPS, ROS (reactive oxygen species), ER stress, influx of calcium ions, and various cytokines such as TNF (tumor necrosis factor) have been described to be stimuli. ASK-1 in turn induces various stress responses including apoptosis and has been described to mediate various cellular responses including survival and differentiation. ASK-1 is a member of the MAPKKK family that constitutes the JNK and p38 MAP kinase (MAPK) cascades. Trx (thioredoxin) was identified as a repressor of ASK-1 and also forms part of the “ASK-1 signalosome”, a high molecular mass complex. ASK has been described to be involved in various diseases associated with autoimmune disorders and neurodegenerative disorders (e.g. H. Nagai et al., J. Biochem. and Mol. Biol., Vol. 40, No. 1, January 2007, pp. 1-6).